US6201953B1 - Method and apparatus for on-board testing of a communication satellite - Google Patents

Method and apparatus for on-board testing of a communication satellite Download PDF

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Publication number
US6201953B1
US6201953B1 US09/206,574 US20657498A US6201953B1 US 6201953 B1 US6201953 B1 US 6201953B1 US 20657498 A US20657498 A US 20657498A US 6201953 B1 US6201953 B1 US 6201953B1
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processor
receiver channel
channel
test
testing
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US09/206,574
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English (en)
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Robert E. Dwyer
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Northrop Grumman Corp
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TRW Inc
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Assigned to TRW INC. reassignment TRW INC. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: DWYER, ROBERT E.
Priority to EP99122070A priority patent/EP1009108A3/en
Priority to JP34705699A priority patent/JP3380198B2/ja
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Assigned to NORTHROP GRUMMAN CORPORATION reassignment NORTHROP GRUMMAN CORPORATION ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: TRW, INC. N/K/A NORTHROP GRUMMAN SPACE AND MISSION SYSTEMS CORPORATION, AN OHIO CORPORATION
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field
    • H04B7/14—Relay systems
    • H04B7/15—Active relay systems
    • H04B7/185—Space-based or airborne stations; Stations for satellite systems
    • H04B7/1851—Systems using a satellite or space-based relay
    • H04B7/18519—Operations control, administration or maintenance

Definitions

  • This invention relates generally to earth-orbiting communication satellites and, more particularly, to techniques for testing communication satellites.
  • communication satellites have multiple independent communication channels, each of which is subject to the introduction of data errors due to faulty components or unwanted signals impressed on the channel.
  • analog or frequency domain testing has been performed by electrical ground support equipment (EGSE) prior to launch of the satellite, and has imposed a significant burden in terms of additional cost and weight.
  • EGSE testing has required the use of multiple test points in the communication system, to make electrical connection with each communication channel. For example, in a 64-channel satellite, an equal number of couplers, attenuators and associated cables are required.
  • the nature of the integration and test procedure is such that, as a practical matter, these additional components must be carried with the satellite into orbit, even though they are only used during testing on the ground.
  • bit error rate testing may be performed while the satellite is in orbit, bit error rate testing does not provide a complete and accurate measure of channel quality and cannot reliably predict communication channel errors.
  • the apparatus of the invention comprises the following onboard components: a processor used for a variety of satellite control and communication functions; a memory for storing a testing module for loading and execution in the processor; a synthesizer for generating test signals under control of the processor when executing the testing module; and a switch controllable by the processor to connect a test signal from the synthesizer to a selected receiver channel to be tested.
  • the selected receiver channel includes an amplifier and an analog-to-digital converter for converting signals received by the receiver channel to digital form for processing by the processor, and the testing module includes a signal analysis sub-module, for analyzing the test signal applied to the receiver channel under test after the test signal has passed through the receiver channel components.
  • each receiver channel in turn can be tested using onboard components.
  • the synthesizer is controlled to generate a signal at a frequency normally handled by the receiver channel under test; and the signal analysis sub-module performs a fast Fourier transform (FFT) function to analyze the receiver channel under test in the frequency domain.
  • FFT fast Fourier transform
  • the apparatus is also capable of testing a plurality of transmitter channels in the same communication satellite.
  • the apparatus further comprises means for coupling a test signal from the synthesizer to a selected transmitter channel, and means for coupling output from the selected transmitter channel to the processor, for analysis of transmitter channel performance using the signal analysis sub-module.
  • the invention may also be defined in terms of a novel method for onboard testing of a communication satellite having a plurality of receiver channels.
  • the method comprises the following steps performed on the satellite: storing a testing module in an onboard memory; loading the testing module into a processor used primarily for a variety of satellite control and communication functions; executing the testing module functions in the processor; generating test signals in an onboard synthesizer under control of the processor when executing the testing module; and connecting a test signal generated in the synthesizer to a selected receiver channel to be tested, through a switch controlled by the processor.
  • the selected receiver channel includes an amplifier and an analog-to-digital converter for converting signals received by the receiver channel to digital form for processing by the processor.
  • the method further includes the steps of analyzing, in a signal analysis sub-module, the test signal applied to the receiver channel under test after the test signal has passed through the receiver channel components; and testing each receiver channel in turn, using the foregoing steps of generating test signals, connecting them to selected receivers in turn, and analyzing the test signals after processing by the receiver channels.
  • the step of generating test signals in the synthesizer includes generating a signal at a frequency normally handled by the receiver channel under test; and the step of analyzing in the signal analysis sub-module includes performing a fast Fourier transform (FFT) function to analyze the receiver channel under test in the frequency domain.
  • FFT fast Fourier transform
  • the method may also comprise the steps of coupling a test signal from the synthesizer to a selected transmitter channel of the communication satellite; coupling output from the selected transmitter channel to the processor; and analyzing the performance of the selected transmitter channel performance using the signal analysis sub-module.
  • the present invention represents a significant advance in the field of testing communication satellites.
  • the invention provides a convenient and reliable technique for testing communication satellites in the frequency domain, both on the ground and while in orbit, with little incremental cost or weight penalty.
  • FIG. 1 is a block diagram of a satellite communication system in accordance with the present invention.
  • the present invention pertains to testing techniques for communication satellites.
  • testing of satellite communication systems in the frequency domain required the addition of costly equipment to facilitate connection to electrical ground support equipment (EGSE).
  • EGSE electrical ground support equipment
  • relevant components of a communication satellite include a receive antenna, indicated by reference numeral 10 , and N receiver channels, one of which is shown at 12 .
  • Each receiver channel includes a low-noise amplifier 14 and an analog-to-digital converter 16 , as well as other conventional components such as filters and mixers, which are not shown in the drawing. It will be understood that some of the receiver channel components may be shared among the channels, depending on design details.
  • the communication satellite also includes a processor/computer (P/C) 20 , which performs a variety of tasks, most of which are unrelated to the present invention.
  • P/C processor/computer
  • the present invention includes two additional components of the communication system: a memory 22 and a synthesizer 24 that includes a voltage-controlled oscillator (VCO).
  • the synthesizer 24 receives commands from the P/C 20 over line 26 , and generates a sinusoidal signal on output line 28 , at a frequency selected in accordance with the particular channel being tested. Usually, the selected frequency will be at the center of a frequency band used by the channel under test.
  • the synthesizer 24 is also capable of modulating a carrier signal with test data, for purposes of performing bit error rate testing.
  • the synthesizer output is routed to a selected receiver channel by a 1 ⁇ N switch 30 , under control of command signals received over line 32 from the P/C 20 .
  • Each receiver channel includes a coupler 34 , through which the synthesizer output signal, on line 36 , can be injected into the input of the low-noise amplifier 14 .
  • the synthesizer 24 and the switch 30 cooperate to impress a desired analog test signal on the selected receiver channel, such as receiver channel 12 .
  • the memory 22 contains control software needed to operate the receiver in a test mode.
  • the control software may be installed in the memory before launch, or may be uploaded when the satellite is in orbit.
  • the software is loaded into the P/C 20 over line 38 .
  • the P/C then executes the software, which controls the generation of signals in the synthesizer 24 , switching of these signals through switch 30 to a selected receiver channel 12 and analysis of resulting signals output by the analog-to-digital converter 16 , on line 40 , in response to input of the analog test signals derived from the synthesizer.
  • the software loaded into the P/C 20 also includes a fast Fourier transform (FFT) module that provides an analysis of the output test signal in the frequency domain.
  • FFT fast Fourier transform
  • Three categories of results are obtainable from the FFT data: a measure of carrier-to-noise ratio, the frequency response of the channel, and detection of possible spurious signals from various sources, which may affect the reliability of the channel.
  • the FFT results as indicated on output line 42 , may be down-linked to a ground station (not shown) for further processing and analysis, or may be further analyzed in the P/C 20 .
  • Conventional down-link data from the satellite is transmitted over line 44 from the P/C to a transmission subsystem 46 , and from there to a transmit antenna 48 . It will be understood that the latter may be a separate structure from the receive antenna 10 , or else a single antenna structure may be shared by the transmit and receive functions of the satellite. Typically, there will be a plurality (M) of transmission subsystems, handling M down-link channels. Another feature of the present invention is that a selected down-link channel can be tested in a way that is analogous to the test procedure described above for the receiver channels.
  • the synthesizer 24 is commanded to generate a desired carrier signal, which is coupled to the transmission subsystem 44 of a selected transmission down-link channel, as indicated by broken line 50 .
  • the output of the transmission subsystem 46 is normally connected to a power monitor 52 , from which down-link telemetry data signals are derived, as indicated at 54 .
  • the power monitor 52 is replaced by an output monitor 56 , which includes the power monitor 52 , together with a two-way switch 58 and appropriate filtering and attenuator components, indicated by block 60 .
  • Output from the transmission subsystem 46 to the transmit antenna 48 is connected by a coupler 62 to the switch 58 , which is also controlled by the P/C 20 .
  • One of the M transmission subsystems 46 may be selected for testing by controlling the switch 58 to connect the output from coupler 62 through the filter and attenuator 60 and onto line 64 .
  • the output signal on line 64 is then input to the analog-to-digital converter 16 , through another switch 66 controlled by the P/C 20 .
  • a pure sine wave can be introduced to the selected transmission subsystem 46 and its output analyzed in the P/C 20 in the same way that the receive channels are analyzed as described above.
  • the present invention permits frequency-domain testing and bit error rate testing of receiver channels, both before launch and while the satellite is in orbit. Moreover, only the channel being tested is interrupted for the test, which achieves the same goals as electrical ground support equipment, but without the high cost and additional weight usually associated with this type of testing.
  • a related aspect of the invention applies similar principles to the testing of transmission subsystems.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Astronomy & Astrophysics (AREA)
  • Aviation & Aerospace Engineering (AREA)
  • General Physics & Mathematics (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Monitoring And Testing Of Transmission In General (AREA)
  • Radio Relay Systems (AREA)
US09/206,574 1998-12-07 1998-12-07 Method and apparatus for on-board testing of a communication satellite Expired - Fee Related US6201953B1 (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
US09/206,574 US6201953B1 (en) 1998-12-07 1998-12-07 Method and apparatus for on-board testing of a communication satellite
EP99122070A EP1009108A3 (en) 1998-12-07 1999-11-16 Method and apparatus for on-board testing of a communication satellite
JP34705699A JP3380198B2 (ja) 1998-12-07 1999-12-07 通信衛星の機内検査方法および装置

Applications Claiming Priority (1)

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US09/206,574 US6201953B1 (en) 1998-12-07 1998-12-07 Method and apparatus for on-board testing of a communication satellite

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Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6424913B1 (en) * 1999-02-19 2002-07-23 Astrium Gmbh GPS navigational system and associated process for space applications
US20030176174A1 (en) * 2002-03-15 2003-09-18 Nokia Corporation, Espoo Finland Method and apparatus providing calibration technique for RF performance tuning
US6782330B1 (en) * 2001-03-22 2004-08-24 Lockheed Martin Corporation Satellite signal waveform monitor
US6825801B1 (en) 2003-12-11 2004-11-30 The United States Of America As Represented By The Secretary Of The Navy Outer loop test generator for global positioning system
US20080154502A1 (en) * 2006-12-22 2008-06-26 Tekawy Jonathan A Satellite navigation using long-term navigation information
US20080177430A1 (en) * 2006-12-22 2008-07-24 Tekawy Jonathan A Satellite navigation using long-term navigation information and autonomous orbit control

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8160575B2 (en) * 2001-07-23 2012-04-17 Space Systems/Loral, Inc. Methods for testing multibeam satellite systems using input power telemetry and output noise power
CN112615665B (zh) * 2020-12-14 2022-08-12 航天东方红卫星有限公司 一种小卫星图像智能处理功能整星测试系统及测试方法
CN113204197B (zh) * 2021-04-23 2022-05-20 中国人民解放军国防科技大学 一种带抗扰功能的微小卫星can总线测试装置及应用方法
CN114513263B (zh) * 2022-01-18 2023-10-10 上海卫星工程研究所 火星环绕器器间通信机自主码率切换功能测试系统及方法

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5937004A (en) * 1994-10-13 1999-08-10 Fasulo, Ii; Albert Joseph Apparatus and method for verifying performance of digital processing board of an RF receiver
US6021314A (en) * 1997-05-22 2000-02-01 Advanced Micro Devices, Inc. Free channel selector for selecting an optimal channel

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4010798A1 (de) * 1990-04-04 1991-10-10 Bodenseewerk Geraetetech Demodulatorbaustein und damit aufgebaute signalverarbeitungsschaltung

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5937004A (en) * 1994-10-13 1999-08-10 Fasulo, Ii; Albert Joseph Apparatus and method for verifying performance of digital processing board of an RF receiver
US6021314A (en) * 1997-05-22 2000-02-01 Advanced Micro Devices, Inc. Free channel selector for selecting an optimal channel

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6424913B1 (en) * 1999-02-19 2002-07-23 Astrium Gmbh GPS navigational system and associated process for space applications
US6782330B1 (en) * 2001-03-22 2004-08-24 Lockheed Martin Corporation Satellite signal waveform monitor
US20030176174A1 (en) * 2002-03-15 2003-09-18 Nokia Corporation, Espoo Finland Method and apparatus providing calibration technique for RF performance tuning
US20060160510A1 (en) * 2002-03-15 2006-07-20 Nokia Corporation Method and apparatus providing calibration technique for RF performance tuning
US7203472B2 (en) * 2002-03-15 2007-04-10 Nokia Corporation Method and apparatus providing calibration technique for RF performance tuning
US6825801B1 (en) 2003-12-11 2004-11-30 The United States Of America As Represented By The Secretary Of The Navy Outer loop test generator for global positioning system
US20080154502A1 (en) * 2006-12-22 2008-06-26 Tekawy Jonathan A Satellite navigation using long-term navigation information
US20080177430A1 (en) * 2006-12-22 2008-07-24 Tekawy Jonathan A Satellite navigation using long-term navigation information and autonomous orbit control
US8099186B2 (en) * 2006-12-22 2012-01-17 The Boeing Company Satellite navigation using long-term navigation information and autonomous orbit control
US8676501B2 (en) 2006-12-22 2014-03-18 The Boeing Company Satellite navigation using long-term navigation information

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JP2000183833A (ja) 2000-06-30
EP1009108A3 (en) 2002-08-07
EP1009108A2 (en) 2000-06-14
JP3380198B2 (ja) 2003-02-24

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